I have been shooting a wide variety of loads in testing a 45 colt and one factory load that has been shooting particular well has been the 335 grain 45 colt +P by Double Tap, another is Grizzly's 335 WLN.

All the high end manufactures(DT,BB,Grizzly) make quality ammo its just what your gun is going to like the best. As for price you get what you pay for..